President Pranab Mukherjee on Monday paid tribute to Sardar Vallabhbhai Patel on his birth anniversary.The President and his staff paid floral tributes at Vallabhbhai Patel's portrait in the Durbar Hall of Rashtrapati Bhavan.Vallabhbhai Patel was born on October 31, 1875, in Nadiad, a small village in Gujarat. After independence he was instrumental in integration of princely states into the Union of India. In 1991, he was conferred with Bharat Ratna for his services to the nation.He was India's first Deputy Prime Minister and the Home Minister. He was popularly known as the 'Iron man' of India.